Material for parts subjected to friction



Patented Nov. 7, 1933 PATENT OFFICE MATERIAL FOR PARTS SUBJECTED T FRICTION Oskar Brandenberger, Zurich, Switzerland N0 Drawing. Application March 20, 1930, Serial No. 437,611, and in Germany July 17, 1929 2 Claims.

This invention relates to parts subjected to friction, such as bearings and the like, and its object is to provide an improved material for parts subjected to friction, orbearings, said parts or bearings-being formed according to the inven- 5 tion of copper alloycontaining sulphur, notably bronze or red metal alloy containing up to 4% of sulphur. Such bronze or alloy is a Cu-Sn-Znalloy, designated as red metal and given under Rotguss in Din. The word Din is the accepted abbreviation for the German words corresponding to the English German Industry Standards.

Under the term Rotguss are to beunderstood alloys of copper with tin and zinc, with or with,- out the addition of lead and other impurities. The best known Rotgusses are: the German Eisenbahn-Rotguss Rg 9, containing 85% copper, 9%

tin and 6% zinc; Rotguss Hg 5 containing 85%.

copper, 5% tin, 7% zinc and 3% lead; and Rotguss Hg 10 (machine bronze) containing 86% copper, 10% tin and 4% zinc.

As a result of the addition of sulphur the antifriction properties of the. alloy are much' improved and the hardness and lasting properties thereof are increased, Whilst any tendency to- Wards porosity is diminished.-

tent of the material should exceed 4%, as with some alloys when the sulphur content exceeds 4% a copper matte product rich in sulphur is liable to be formed, said product, if formed, separating out from and floating on the molten alloy owing to its lower specific gravity.

The sulphur may be added: to the alloy either in an uncombined state or as a sulphur com- It is not always advisable that the sulphur conpound. As a result of this addition, chiefly cop-' 'of eutectoid is considerably diminished with increasing sulphur content.

The improvement in the anti-friction properties of bronze-and red metal alloys by the addition of sulphur is very marked. Moreover, bearing surfaces of sulphur bronze have three to four times the. working life of those made from alloy without sulphur but otherwise of the same composition. Not only is the wearing away of sulphur bronze alloys considerably less than that of similar alloys without sulphur, but bearings made from such sulphur bronze alloys can be submitted to considerably greater surface pressure. The coefiicient of friction of sulphur bronze alloy is considerably less than that of similar alloys without sulphur.

What I claim is;-

l. A bearing metal mostly consisting of copper, tin, zinc, lead'and up to 4% sulphur with a major proportion of copper. V

2. A bearing made of an alloy of the bronze and redbrass type, mostly consisting of copper, tin, zinc, lead and up to 4% sulphur with a major proportion of copper.

OSKAR BRANDENBERGER. 

